One person. Where the effects of every social system are ultimately experienced. Mind, body, and the moment-to-moment perception that builds your version of reality. The scale at which all the others are eventually felt.

Two people. The minimum social unit. Trust, mutual understanding, and the dyadic dynamics out of which all larger groupings are eventually built. Most of what holds at this scale dissolves quickly above it.

A handful of people, deeply connected. The most basic group humans have organised into for as far back as anyone can trace. Childcare, eldercare, intimate trust. The scale at which most of daily life is actually lived, even in the modern world built on top of it.

About a hundred and fifty people. Roughly the limit of stable social relationships any individual can maintain - what the anthropologist Robin Dunbar identified as the natural human group size. Workplaces, school grades, sports teams, neighbourhood blocks, religious congregations, tight-knit online groups. Status is direct; everyone knows everyone by name and face.

Ten thousand people. Some everyone knows; most are strangers. Local politics, schools, basic services, clubs. The scale at which institutions begin to matter more than personal relationships. The first level where impersonal rules are necessary rather than optional.

A million people. Most are strangers. Markets, infrastructure, and bureaucratic procedure emerge as necessary substitutes for personal trust. The scale at which most modern humans actually live, even though much of culture and politics still imagines smaller groups.

Tens of millions. Sub-national governance. Cultural variation, regional economies, distinct legal cultures even within a single country. California, Bavaria, Catalonia, Sao Paulo state. Often the level at which the actual administrative work of government happens, while national politics gets the headlines.

Hundreds of millions. The dominant political unit of the modern era. Where sovereignty, citizenship, currency, and most of the news happen. The scale at which most of The Now operates: debt, demographics, identity, the rise of one country and the slow recalibration of another.

Multiple states aligned. NATO, the EU, BRICS, the broader "West" or "Global South." Where geopolitics actually happens - rivalries, alliances, trading systems, the rules of the international order. The unwinding of the postwar settlement is being negotiated mostly at this scale.

8.3 billion people. The whole human enterprise. Climate, pandemics, the global commons, the long-run trajectory of the species. The largest scale at which human society actually organises itself - and the scale at which its institutions are weakest. What holds here cannot be enforced; it has to be negotiated.